Room 5/4 is an intricate wooden gate that swings westward into the Graveyard Branch of the Tree. The carvings are full of maudlin goblin imagery about life and death. Past the gate, adventurers can see the Graveyard Branch, but a bit distorted as all the gate's openings are covered in magical slime - the ectoplasmic remains of Ghost Slimes.
If one tries to open or get by the gate without singing the passtune (known to Gargu and Rest, but no others of note), the spirits of the slimes animate as small, cube-like, biting mouths. Adventurers must save vs paralysis. On a failure, they are restrained by the biting ectoplasm. Regardless, the enchantment notifies Rest.